[Data Retriever] Adding Spatial Dataset Support - Kush Kothari

A major requirement for the current status of the dashboard is the implementation of a download and install pipeline for tables having spatial data in the form of vector images/data. According to the retriever docs, currently the retriever library uses the PostGIS extension for the same. Therefore, the install process to be used for the dashboard will make use of the postgres engine. The spatial datasets are already tested for only download and changes are detected using the md5 hash. This proposal will further that, into proper install of these datasets into Postgres and find out diffs in the databases using PostGIS joins. The results obtained will then be converted into HTML diffs just like we do for non-spatial databases.